Thermal Disinfection

At a temperature over 70 °C legionella are eridicated instantly. The method of thermal disinfection is based on heating the whole pipe network for at least 5 minutes up to more than 72 °C - taps and fittings included. 72 °C hot water must flow through each tap for 3- 5 minutes, to achieve a real disinfection.

Depending on the region, lime outfall starting at 60 °C cause major problem in the piping.

The risk to scald oneself needs to be considered when using thermal disinfection in nursing homes, hospital etc.

Naturally the thermal disinfection captures only the warm water system.

As in buildings with modern heating systems cold water can be warmed up over 20 °C, a solid increase of legionella in the cold water system is possible.

If in addition structural defects, such as too large dimensioned pipes, bad isolated warm water or heating pipes exist, the cold water temperature can even increase over 25 °C.


Using (UV-) radiation for disinfection is among the physical methodes the only alternative to thermal solutions (according to technical rules and standards DVGW W551 april 2004).

This procedure is used were elevated temperature is not possible or not wanted.

No foreign substances are added, however this method only selectively efficient and has no repository effect.

Chemical disinfection

For a permanent chemical disinfection only permitted chemicals are allowed for use. In the process, limits and the formation of disinfection by-products are to be considered.

At a batch disinfection chemicals are added in high concentration, here disinfecting agents not corresponding to the list of preparation substances (German Federal Environmental Agency) are also applicable. Afterwards a cleaning of the pipe network is required, to remove the chemicals used .

During the procedure it has to be assured that no drinking water is extracted.